Downhole operations such as drilling, hydraulic fracturing typically result in the generation of particulate residue, frequently where the operations are carried out in rock formations that are not well consolidated. The presence of such particulates, such as sand, can interfere with extraction or filling of the drilled borehole or reservoir, since the particulates can clog or damage equipment, or can interfere with stimulation or extraction processes.
While equipment such as filters and screens may be used to reduce, collect, or minimize the amount of particulates in downhole environments, other methods have been considered such as injecting concrete compositions downhole to agglomerate the particulates into a porous mass that does not have to be filtered. Such methods are sometimes referred to as “screenless completion techniques” and involve injecting a consolidating fluid including, for example, a resin, curing agent, and catalyst and a wetting agent. Other methods include injecting a consolidating composition of colloidal particles such as silica, and a modifier to adjust pH or ionic strength to form a gel that prevents particulate mobility.
Geopolymers include inorganic polymers based on inexpensive mineral or mineral-derived materials such as silicas, silicates, aluminosilicates, etc. and are of interest because such materials can be cured by action of acid or alkali and form stable networks that provide a higher degree of strength and interconnectivity, and hence improved durability and longevity. For example, materials such as silicates including alkali-activated slags have been used as cements.
However, there remains a need for injectable materials that have improved control over consolidation and bulk properties in reducing particles after consolidation.